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