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