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