A Sankey diagram is a type of flow diagram where the Link thickness is proportional to the flow quantity.

This sample customizes LayeredDigraphLayout.

{
    "class": "go.GraphLinksModel",
    "nodeDataArray": [
      {"key": "Source-Group-01", "text": "Mobile", "color": "#b300ff"},
      {"key": "Source-Group-02", "text": "GCP", "color": "#ff6b00"},
      {"key": "Source-Group-03", "text": "OnPrem", "color": "#00ff6b"},
      {"key": "Source-Group-04", "text": "SaaS", "color": "#ff00b3"},
      {"key": "Pattern-01", "text": "Message Based", "color": "#254d57"},
      {"key": "Pattern-02", "text": "Web Based", "color": "#254d57"},
      {"key": "Pattern-03", "text": "Cloud Based", "color": "#254d57"},
      {"key": "Pattern-04", "text": "Event Based", "color": "#254d57"},
      {"key": "Pattern-05", "text": "File Based", "color": "#254d57"},
      {"key": "Target-Group-01", "text": "GCP", "color": "#ff6b00"},
      {"key": "Target-Group-02", "text": "OnPrem", "color": "#00ff6b"},
      {"key": "Target-Group-03", "text": "SaaS", "color": "#ff00b3"},
      {"key": "Target-Group-04", "text": "MarketPlace", "color": "blue"}
    ],
    "linkDataArray": [
      {"from": "Source-Group-01", "to": "Pattern-01", "width": 5},
      {"from": "Source-Group-02", "to": "Pattern-01", "width": 5},
      {"from": "Source-Group-03", "to": "Pattern-01", "width": 5},
      {"from": "Source-Group-04", "to": "Pattern-01", "width": 5},
      {"from": "Pattern-01", "to": "Target-Group-01", "width": 5},
      {"from": "Pattern-01", "to": "Target-Group-02", "width": 5},
      {"from": "Pattern-01", "to": "Target-Group-03", "width": 5},
      {"from": "Source-Group-01", "to": "Pattern-02", "width": 5},
      {"from": "Source-Group-02", "to": "Pattern-02", "width": 5},
      {"from": "Source-Group-03", "to": "Pattern-02", "width": 5},
      {"from": "Source-Group-04", "to": "Pattern-02", "width": 5},
      {"from": "Pattern-02", "to": "Target-Group-01", "width": 5},
      {"from": "Pattern-02", "to": "Target-Group-02", "width": 5},
      {"from": "Pattern-02", "to": "Target-Group-03", "width": 5},
      {"from": "Source-Group-01", "to": "Pattern-03", "width": 5},
      {"from": "Source-Group-02", "to": "Pattern-03", "width": 5},
      {"from": "Source-Group-03", "to": "Pattern-03", "width": 5},
      {"from": "Source-Group-04", "to": "Pattern-03", "width": 5},
      {"from": "Source-Group-01", "to": "Pattern-04", "width": 5},
      {"from": "Source-Group-02", "to": "Pattern-04", "width": 5},
      {"from": "Source-Group-03", "to": "Pattern-04", "width": 5},
      {"from": "Source-Group-04", "to": "Pattern-04", "width": 5},
      {"from": "Source-Group-01", "to": "Pattern-05", "width": 5},
      {"from": "Source-Group-02", "to": "Pattern-05", "width": 5},
      {"from": "Source-Group-03", "to": "Pattern-05", "width": 5},
      {"from": "Source-Group-04", "to": "Pattern-05", "width": 5},
      {"from": "Pattern-03", "to": "Target-Group-03", "width": 5},
      {"from": "Pattern-02", "to": "Target-Group-04", "width": 5},
      {"from": "Pattern-05", "to": "Target-Group-01", "width": 5},
      {"from": "Pattern-04", "to": "Target-Group-02", "width": 5},
      {"from": "Pattern-05", "to": "Target-Group-02", "width": 5}
    ]
  }