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