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