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