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