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