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