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