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