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