[Batfish]

The color of the jumper shouldn't matter.

If you have an electronics store near you, stop in there with your speed controller and ask them if they have a jumper that would fit the spot you want it to. I'd expect they can help out.

Also, consider that all a jumper does is close the electrical circuit so you could even (carefully) solder a small piece of wire between the two poles to complete the circuit. Removal isn't as easy as a jumper, but it's less likely to fall off.