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