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