Great detective work on the ribbons, guys; I was ready to jump in that the first one is a Legion of Merit, but Hugh caught that one. However, I really don't think there are any WWI ribbons hidden here; also he has 6 Overseas Bars - 3 years service outside the US during wartime. So, I think that limits him to WW2 and I think we have to stay looking to the WW2 and possibly post-WW2 period for awards. Mainly, because I think this picture could even go into the late 40s or early 50s period and Wayne might be right that it's a retirement photo.
The patch is definitely the SHAEF patch; but that headquarters was dissolved in July 1945. However, the patch continued. First as as US forces became USFET - US Forces European Theater in 1945, then becoming EUCOM - European Command in 1947 - finally in 1952 US Army Europe - USAREUR - retaining the SHAEF patch as it's SSI; which it in fact, remains as the USAREUR SSI even today. So, our colonel's picture could have even been taken after 1952 - and still have that patch. I wish we could see his right shoulder to see if there is a combat patch.
I'm also certain - as others have said - that the ring is a West Point class ring; while still not conclusive, West Pointer's wear their class rings on the left hand as a rule - often with or without wedding rings. While not certainly a guarantee, other universities tend (though I'm sure not always) wear this type ring on the right finger. The almost visible engraving on the sides suggest a class ring over some type of jewelry signet ring. And the cavalry connection - with the embroidery insignia, especially the eagles that look almost bullion - smell of Old Army. As others also have stated.
I guess I am only trying to say, don't limit yourself to SHAEF rosters; because it's equally likely - if not more - that he's serving in one of the later HQs. Nonetheless, if you want to try and ask some old SHAEF vets, they have a website: http://www.shaef.org/index.html