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