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