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