One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,5)(3,7,8,6)(9,10)(11,16)(12,22)(13,27)(14,29)(15,19)(17,24)(18,30)(20,34)(21,35)(23,37)(25,32)(26,38)(28,31)(33,39)(36,40)(2,5)(6,7)(9,11,15,13)(10,16,19,27)(12,23,26,39)(14,28,30,21)(17,32,34,40)(18,35,29,31)(20,36,24,25)(22,37,38,33)(9,12,13,24,15,26,11,20)(10,17,16,22,19,34,27,38)(14,25,21,23,30,36,28,39)(18,33,35,40,29,37,31,32)(1,3,4,8)(2,6,5,7)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.