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