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