I don't think it's necessary to twist them, they aren't signal wires, but it does make routing easier. That's probably why they did it.
If you want to twist wires together like that the trick is to lightly restain one end of the wires then chuck the other ends in a drill chuck. Spin until you like it.
If you want to twist wires together like that the trick is to lightly restain one end of the wires then chuck the other ends in a drill chuck. Spin until you like it.