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