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