This is a tricky game to diagram!
Since there are several rules relating to the order in which the cars (V, W, X, Z) can be worked on at a particular factory, I used the years (1, 2 and 3) as a baseline and arranged the factories (F, G, H, J, K) vertically.
What we end up with is a grid 5 spaces high (representing each factory) and 3 spaces wide (representing years 1 through 3). The actual cars (V, W, X, Z) will be placed into the spaces:
1 2 3
F _ _ _
G _ _ _
H _ _ _
J _ _ _
K _ _ _
The big inferences here are that if X is manufactured at a factory, Z will be manufactured the next year, and W the year after that. We also know that Z cannot be manufactured in two locations in the same year, so only one "Z" variable will be used per year. Since X
Z, we have the same limitation on repeating X in years 1 or 2, since that would force two factories to manufacture Z in years 2 or 3.
I hope this helps you get started! Good luck!