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)(25,26,31,29,30,33,28,39)(27,34,37,36,38,32,35,40)(1,2)(3,6)(4,5)(7,8)(9,11,13,18)(10,14,16,23)(12,20,21,17)(15,24,19,22)(25,27,30,38)(26,32,33,34)(28,35,31,37)(29,40,39,36)(9,12,13,21)(10,15,16,19)(11,17,18,20)(14,22,23,24)(25,28,30,31)(26,29,33,39)(27,35,38,37)(32,40,34,36)(2,5)(6,8)(10,16)(14,23)(15,19)(22,24)(25,29,31,33,30,39,28,26)(27,36,37,32,38,40,35,34)(1,3,4,7)(2,6,5,8)(25,28,30,31)(26,29,33,39)(27,37,38,35)(32,36,34,40)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.