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