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