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