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