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