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