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