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