Well, not exactly a digram, but I will describe the IBM FastT200 RJ25 to DE9 wiring. This inforamtion was given to me by a friend, and I both hope it to be accurate, and hope it would help whoever needs it.
Another friend noted that the diagram is upside-down, which might be the case. It might be that you need to reverse either one, or both of the lists. However, even this to begin with might be better than none.