The project has a page about "wiring" [1] which also has a table with the needed parts to make your own cable (that's what I ended up doing).

In my case it was more hassle to look up how to dismantle the unit to get to the motherboard (I recommend looking up your unit's service manual), attaching the module and routing the cable are trivial.

[1] https://github.com/revk/ESP32-Faikin/wiki/Wiring