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