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