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