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