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