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