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