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