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