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