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