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