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