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