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