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