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