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