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