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