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