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