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