ConnectionDefaults.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"
      }
    ],
    connectionDefaults: {
      type: "polyline",
      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",
        content:{
          text: "State 1"
        },
        x: 20,
        y: 20
      },
      {
        id:"2",
        content: {
          text: "State 2"
        },
        x: 200,
        y: 20
      }
    ],
    connections:[
      {
        from: "1",
        to: "2"
      }
    ],
    connectionDefaults: {
      selection: {
        handles: {
          fill: {color: "#ff6358"},
          stroke: {color: "#333"},
          height: 8,
          width: 8
        }
      }
    }
});
</script>