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