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