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