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