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