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