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