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