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