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