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