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