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