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