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