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