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