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