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