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