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