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