Upon close scrutiny of the HD screencap of Riker's diploma and comparing the word length and spacing on some replicas I found online through a Google search, it would be appear the wording used for some is pretty much dead-on. From what I can tell, this makes up the main body of the document:
Upon notification of the Faculty and the Board of Trustees of
WILLIAM T. RIKER/LT. CDMR. DATA SOONG/ETC.
Having fulfilled the [illegible] requirements prescribed by the Trustees of the Academy and after a thorough examination upon all studies and skills pertaining to Starfleet service, is conferred the degree of MASTER OF SCIENCE, with all the duties, responsibilities and privileges thereunto appertaining.
In witness thereof, the Trustees have caused this diploma to be issued bearing the Great Seal
of the United Federation of Planets, effective stardate 00000.00.
President, Board of Trustees
Chief of Staff
There's the one word highlighted in bold I can't quite make out, and even the HD screencap isn't clear enough to determine the titles/roles of the four signataries, but that aside I think that's the bulk of the text.
EDIT: The top signatures I think I can discern as actually being Patrick Stewart (S #1) and Gene Roddenberry's (S #2), if I'm not mistaken. Also extrapolated the title/role for each based on some of the replicas I found online through Google.
EDIT #2: Something to note regarding the silk screening. From what I can see, I think all the white details are on the top layer, with all the blue details on the bottom layer. There appears to be black vinyl running along the sides of the acrylic.