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