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