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