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