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