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