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