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