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