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