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