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