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