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