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