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