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