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