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)(11,17)(12,14)(13,21)(15,19)(16,20)(18,24)(22,23)(27,34)(31,39)(35,40)(36,38)(1,3,5,8)(2,6,7,4)(10,14)(15,23)(16,21)(17,24)(25,26,29,33)(27,35,34,40)(28,32,30,37)(31,38,39,36)(9,11,12,18)(10,15,14,23)(13,22,20,19)(16,24,21,17)(25,27,29,34)(26,31,33,39)(28,36,30,38)(32,40,37,35)(1,4,5,6)(2,3,7,8)(10,16)(13,20)(14,21)(15,24)(17,23)(19,22)(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.