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