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