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