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