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