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