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