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