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