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