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