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