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