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