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