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