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