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