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