Avast Skood,
Not too many illustrations come to mind; there are a few clinical (profile, plan and detail) drawings to be found in Steve O'Shea's Colossal squid fact sheet, and at TOLWEB's
Mesonychoteuthis page.
They're not illustrations, but pages 7 and 8 of the
Tentarcticles (Mesonychoteuthis / Colossal Squid) thread in the
Physiology & Biology forum feature photos of the lifesize
Mesonychoteuthis model produced for a Discovery channel special. Quite startling, especially the photos taken in a dark swimming pool.
Best wishes for your project.
Yours truly,
Clem