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