How to properly shield a < 5v Circuit from EMI from a 220v motor?
Flyback diode on the contactor coil is usually a good idea. Also you've drawn the power supply upside down.

Your drive setup is a bit weird: what is the whole R1/C1/R2 setup for?

EMI can be either conducted or radiated. Normally you'd investigate to determine which, but this requires at the very least a scope. So you'll have to experiment with:


put the device in a grounded metal box (not possible in your case if you're using the PCB antenna radio)
attach ferrite chokes to all pairs of external leads