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