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