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