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