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