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