First, forget auto-tracing. There is no instant-gratification magic bullet here. Auto-tracing is a cheap trick and doesn't generate clean line drawings.
The drink dispenser and its three insert details are drawn by isometric method, ensuring mechanically-correct proportion and scale. (The defacto standard for technical drawings for instructions, parts explosions, cutaways, etc., etc.). The human figures and hands just serve as "decoration" enhancements of the technical information being depicted to put it in an actual-use scene. The man operating the dispenser is manually drawn, perhaps (but not necessarily) using a reference photo shot from an approximately isometric viewpoint. The insert of the woman is just a similar manual line drawing, perhaps (but not necessarily) using an ordinary perspective photo. "Not necessarily" because a skilled illustrator can draw such figures to fit a scene without using photos (much like a comic book illustrator would).
JET