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