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