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