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