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