Nice work, I"m not sure from the pics whether the cable has to flex or not but if it doesn't and you need to just run it back from stationary sensors I would run the cable straight down to the base through a hole in the main body and then embed it in a trench which you could fill with black silicon. That way it would be hidden completely. Hope that makes sense. The groove or trench could be cut into the base when cutting the main sections.

If you are using hall sensors mount the magnet on the moving arm and the sensor on the stationary base then you should have no worries routing a cable.