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