IF transformer color codes
There's no standard that I've found, unfortunately.  But, there are some common conventions.

This page has more detailed information than most pages I've found on the subject:
https://www.electronics-tutorials.com/filters/if-amplifier-transformers.htm

It includes turns ratios, impedances, intended application, core color, etc., for a small sample of IF transformers.  The general advice on that page is to consult the datasheet for the part number, if you can find it.  Of course, most of the time there is no part number to be found.

An LCR meter can help identify the winding inductances in a transformer.