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