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)(11,15)(12,20)(13,22)(14,18)(16,21)(17,23)(19,24)(25,26,29,34)(27,35,37,31)(28,33,30,32)(36,40,38,39)(2,5)(6,8)(9,11,14,12)(10,15,18,20)(13,19,23,21)(16,22,24,17)(25,27,29,37)(26,31,34,35)(28,38,30,36)(32,39,33,40)(9,12,14,11)(10,16,18,24)(13,19,23,21)(15,22,20,17)(26,32)(27,36)(28,30)(33,34)(37,38)(39,40)(1,3,4,7)(2,6,5,8)(11,12)(15,20)(16,24)(19,21)(25,28,29,30)(26,33,34,32)(27,36,37,38)(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.