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