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