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