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