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