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