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