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