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