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