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