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