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