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