<div id="diagram"></div>
<script>
$("#diagram").kendoDiagram({
    connections: [{
        from: { x: 100, y: 150 },
        to: { x: 300, y: 150 }
    }]
});

var diagram = $("#diagram").getKendoDiagram();
var connection = diagram.connections[0];

// Set new position
connection.position({ x: 50, y: 100 });
</script>