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)(11,14)(12,15)(13,16)(17,21)(18,24)(19,23)(20,22)(25,26,30,34,31,28,29,33)(27,32,38,35,36,39,37,40)(2,5)(6,8)(9,11,17,18,12,19,13,20)(10,14,21,24,15,23,16,22)(25,27,29,37,31,36,30,38)(26,32,33,40,28,39,34,35)(3,7)(6,8)(10,15)(11,18)(13,17)(14,22)(19,20)(23,24)(25,28,31,26)(27,35,36,40)(29,33,30,34)(32,37,39,38)(1,3,4,7)(2,6,5,8)(27,36)(32,39)(35,40)(37,38)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.