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