There is an oop book (plus it is in German) which has all the information that you want/need as far as I understand:
Deutsche Marineinfanterie 1938-1945: Das Schicksal der Marinestoßtrupps, der M.A.A. 531 (von Diest) und anderer infanteristisch eingesetzter Einheiten der Kriegsmarine
ISBN-10 : 3880427992
ISBN-13 : 978-3880427990
But beware - even if you are not discouraged by a book in German, the prices this commands may do so. I found offers from 40 € to 80 € plus shipping on various plattforms.
The wiki entry for the Kriegsmarine has a plate showing unifomrs and markings - this might be helpful too: