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