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