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)(25,26,31,36)(27,37,38,32)(28,29,34,33)(30,35,39,40)(1,2,5,4)(3,7,8,6)(10,12)(15,17)(16,20)(22,23)(25,27,31,38)(26,32,36,37)(28,35,34,40)(29,30,33,39)(1,3,5,8)(2,6,4,7)(10,12)(11,18)(13,21)(22,23)(28,34)(29,33)(30,39)(35,40)(3,8)(6,7)(9,11,14,18)(10,15,12,17)(13,19,21,24)(16,22,20,23)(25,28)(26,33)(27,35)(29,36)(30,37)(31,34)(32,39)(38,40)(1,3)(2,7)(4,6)(5,8)(9,12,14,10)(11,15,18,17)(13,20,21,16)(19,22,24,23)(25,29,31,33)(26,34,36,28)(27,30,38,39)(32,40,37,35)(1,4,5,2)(3,6,8,7)(9,13)(10,16)(11,19)(12,20)(14,21)(15,22)(17,23)(18,24)(25,30)(26,35)(27,33)(28,37)(29,38)(31,39)(32,34)(36,40)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.