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