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