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)(11,18)(12,15)(13,16)(14,20)(17,22)(19,23)(21,24)(25,26)(27,28)(29,32)(30,33)(31,35)(34,36)(37,38)(39,40) involution — undirected(2,4)(6,7)(9,11,15,13)(10,16,12,18)(14,19,22,21)(17,23,20,24)(27,31)(28,35)(34,39)(36,40)(9,10,15,12)(11,18,13,16)(14,17,22,20)(19,24,21,23)(25,27,30,31)(26,28,33,35)(29,34,38,39)(32,36,37,40)(1,3,5,8)(2,6,4,7)(9,12,15,10)(11,18,13,16)(14,20,22,17)(19,24,21,23)(25,26)(27,28)(29,37)(30,33)(31,35)(32,38)(34,40)(36,39)(1,4,5,2)(3,6,8,7)(9,13,15,11)(10,16,12,18)(14,21,22,19)(17,23,20,24)(25,28)(26,31)(27,33)(29,36)(30,35)(32,39)(34,37)(38,40)(1,3)(2,7)(4,6)(5,8)(9,14)(10,17)(11,19)(12,20)(13,21)(15,22)(16,23)(18,24)(25,29)(26,32)(27,34)(28,36)(30,38)(31,39)(33,37)(35,40) 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.