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