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