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