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