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