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