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