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