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)(11,19)(12,21)(13,20)(14,18)(15,17)(16,22)(23,24)(25,26,29,31)(27,33,35,40)(28,36,37,32)(30,38,39,34)(2,5)(6,8)(9,11)(10,12)(13,16)(14,21)(15,24)(17,22)(18,19)(20,23)(28,37)(30,39)(32,36)(34,38) involution — undirected(3,7)(6,8)(9,12,14,19)(10,16,18,24)(11,20,21,17)(13,23,15,22)(25,27,29,35)(26,30,31,39)(28,38,37,34)(32,40,36,33)(1,3,4,7)(2,6,5,8)(9,13,14,15)(10,17,18,20)(11,16,21,24)(12,22,19,23)(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.