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