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