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