I want to create an application in PYTHON with graphical interface (using pyqt), with a COM automation server. 
So that COM clients could call this app using COM, and this would result in events in the main gui window. But I'm not sure how to integrate pyqt (signals/slots) to COM automation server (using pywin).
Your software is built from three different parts:

The program core - what actually does the stuff.
The GUI - in this case built in pyqt.
The COM server - one more UI that has nothing to do with 2.

Let the COM client do its thing. The output can be doing stuff and updating the GUI interface.
What I am saying is that the two interfaces have nothing to do thin each other.
Using COM automation server and PyQt