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