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