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