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