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