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