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