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