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)(13,15)(14,19)(18,23)(20,22)(21,24)(25,26,31,33)(27,32,35,37)(28,34,36,40)(29,38,39,30)(1,2,4,5)(3,6,7,8)(9,11)(10,14)(12,18)(13,19)(15,17)(16,21)(20,24)(22,23)(25,27,31,35)(26,32,33,37)(28,29,36,39)(30,34,38,40)(10,15)(14,17)(16,22)(21,23)(26,33)(27,35)(28,36)(30,38) involution — undirected(9,10)(11,14)(12,16)(13,15)(17,19)(18,21)(20,22)(23,24)(25,28)(26,34)(27,29)(30,37)(31,36)(32,38)(33,40)(35,39) involution — undirected(9,11)(10,14)(12,18)(13,19)(15,17)(16,21)(20,24)(22,23)(25,29)(26,30)(27,36)(28,35)(31,39)(32,34)(33,38)(37,40) involution — undirected(1,3,4,7)(2,6,5,8)(9,12,13,20)(10,16,15,22)(11,18,19,24)(14,21,17,23)(25,30)(26,29)(27,34)(28,37)(31,38)(32,36)(33,39)(35,40)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.