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