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