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