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