AFAIK it is not possible since the connection is made up of SVG object which itself acts as background image. You can try dashstyle
option while tweaking paint-style and gradients to obtain appropriate arrow as shown in image. For more refer: API DOC
Sample Code:
jsPlumb.Defaults.PaintStyle = {
lineWidth: 4,
strokeStyle: 'rgba(123, 123, 123, 1)',
gradient:{
stops:[[0,"green"], [1,"red"]]
},
dashstyle: "7"
};
Result:
Note: Remember to use jsPlumb.setRenderMode(jsPlumb.SVG)
since dashstyle doesn't work with jsPlumb.CANVAS (by default it is SVG)