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