This can be done at any time while playing as Shay and having the Hexibot in your inventory. Each individual solution varies because the game generates a new solution to the wiring each time. Make the following symbols appear:

Blue: Triangles pointing left and right, triangles pointing up and down.
Yellow: Triangles pointing left and right, triangles split into thirds.
Red: Triangles pointing left and right, colored in triangle upside down.

The only thing that always is the same is that all three wires will originate from the same source. Check your progress by using the charge station.