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