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