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)(11,16)(12,18)(13,19)(14,22)(15,17)(20,24)(21,23)(1,3,5,8)(2,6,7,4)(9,11)(10,16)(12,15)(13,20)(14,21)(17,18)(19,24)(22,23)(25,26)(27,33)(28,36)(29,30)(31,34)(32,37)(35,39)(38,40)(1,2)(3,4)(5,7)(6,8)(10,17)(11,12)(13,23)(14,24)(26,30)(27,34)(28,37)(39,40) involution — undirected(1,4)(2,3)(5,6)(7,8)(9,12,15,11)(10,18,17,16)(13,20,23,22)(14,19,24,21)(25,27)(26,31)(28,38)(29,34)(30,33)(32,40)(35,37)(36,39)(1,3)(2,4)(5,8)(6,7)(9,13,15,23)(10,19,17,21)(11,20,12,22)(14,16,24,18)(25,28)(26,32)(27,35)(29,37)(30,36)(31,39)(33,40)(34,38)(1,4)(2,3)(5,6)(7,8)(9,14)(10,20)(11,21)(12,19)(13,16)(15,24)(17,22)(18,23)(25,26)(27,31)(28,32)(29,30)(33,34)(35,39)(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.