Code

var off = 5;
var or = link.Origin.Bounds;
var dr = link.Destination.Bounds;
var top = 10;

SetLinkPoints(link,
	new PointF(or.Left, or.Y + or.Height / 2),
	new PointF(or.Left - off, or.Y + or.Height / 2),
	new PointF(or.Left - off, top),
	new PointF(dr.Right + off, top),
	new PointF(dr.Right + off, dr.Y + dr.Height / 2),
	new PointF(dr.Right, dr.Y + dr.Height / 2));

void SetLinkPoints(DiagramLink link, params PointF[] points)
{
	link.AutoRoute = false;
	link.Shape = LinkShape.Cascading;
	link.ControlPoints.Clear();
	link.ControlPoints.AddRange(points);
	link.UpdateFromPoints(false, true);
}