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