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