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