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