One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10,16,12,15,20,14,19)(11,21,24,17,26,27,25,22)(13,28,31,34,30,33,29,18)(23,32,37,40,39,36,38,35)(1,3)(2,5)(4,7)(6,8)(9,11,16,24,15,26,14,25)(10,17,12,27,20,22,19,21)(13,23,31,37,30,39,29,38)(18,32,28,40,34,36,33,35)(3,7)(5,8)(9,12,14,20,15,19,16,10)(11,22,24,27,26,17,25,21)(13,28,29,34,30,33,31,18)(23,36,37,40,39,32,38,35)(9,13,14,29,15,30,16,31)(10,18,12,28,20,34,19,33)(11,23,25,38,26,39,24,37)(17,32,27,40,22,36,21,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.