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