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