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