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