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