Connections.selection

<div id="diagram"></div>
<script>
  $("#diagram").kendoDiagram({
    shapes:[
      {
        id:"1",
        content:{
          text: "State 1"
        },
        x: 20,
        y: 20
      },
      {
        id:"2",
        content: {
          text: "State 2"
        },
        x: 200,
        y: 20
      }
    ],
    connections:[
      {
        from: "1",
        to: "2",
        startCap: "FilledCircle",
        endCap: "ArrowEnd",
        selection: {
          handles: {
            fill: {color: "Yellow"},
            stroke: {color: "White"},
            height: 20,
            width: 20
          }
        }
      }
    ]
  });
</script>

<div id="diagram"></div>
<script>
$("#diagram").kendoDiagram({
    shapes: [
      { id: "1", x: 100, y: 100, content: { text: "Shape 1" } },
      { id: "2", x: 300, y: 100, content: { text: "Shape 2" } }
    ],
    connections: [{
      from: "1",
      to: "2",
      selection: {
        handles: {
          fill: "#ff6358",
          stroke: { color: "#333" },
          width: 8,
          height: 8
        }
      }
    }]
});
</script>