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