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