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