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