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