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