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