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