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