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