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