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)(11,16,14,18)(13,20,22,17)(19,24,21,23)(25,26,30,32)(27,33,36,29)(28,31,38,40)(34,39,35,37)(1,2)(3,5)(4,6)(7,8)(9,11,15,14)(10,16,12,18)(13,19,22,21)(17,23,20,24)(25,27,30,36)(26,29,32,33)(28,35,38,34)(31,39,40,37)(1,3,4,7)(2,5,6,8)(10,12)(16,18)(17,20)(23,24)(25,28,30,38)(26,31,32,40)(27,34,36,35)(29,37,33,39)(9,12,15,10)(11,18,14,16)(13,20,22,17)(19,24,21,23)(25,26)(27,29)(28,31)(30,32)(33,36)(34,37)(35,39)(38,40)(9,13,15,22)(10,17,12,20)(11,19,14,21)(16,23,18,24)(25,28)(26,31)(27,35)(29,39)(30,38)(32,40)(33,37)(34,36)(9,14,15,11)(10,18,12,16)(13,21,22,19)(17,24,20,23)(25,29)(26,27)(28,37)(30,33)(31,34)(32,36)(35,40)(38,39)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.