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