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