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