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)(11,19)(12,22)(13,18)(14,16)(15,21)(17,23)(20,24)(25,26)(27,32)(28,34)(29,39)(30,35)(31,33)(36,38)(37,40)(1,3,6,5)(2,7,4,8)(9,11,14,21)(10,15,16,19)(12,20,23,18)(13,17,24,22)(25,27)(26,32)(28,33)(29,36)(30,37)(31,34)(35,40)(38,39)(1,3,6,5)(2,8,4,7)(10,16)(12,23)(15,19)(18,20)(26,33)(27,34)(29,35)(37,38)(1,4,6,2)(3,7,5,8)(9,11)(10,15)(12,20)(13,22)(14,21)(16,19)(17,24)(18,23)(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)(10,17)(11,20)(13,19)(14,23)(15,24)(16,22)(18,21)(25,29,31,35)(26,30,33,39)(27,36,34,40)(28,38,32,37)(9,13,14,24)(10,18,16,20)(11,17,21,22)(12,19,23,15)(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.