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