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