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