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