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