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