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