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