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