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