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)(25,26,30,28)(27,34,37,40)(29,33,31,39)(32,36,35,38)(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)(27,32)(28,30)(29,39)(31,33)(34,38)(35,37)(36,40)(9,12)(10,15)(11,17)(13,20)(14,21)(16,24)(18,19)(22,23)(25,27,29,36,30,37,31,38)(26,32,39,40,28,35,33,34)(12,20)(15,24)(17,19)(21,23)(25,28,30,26)(27,35,37,32)(29,33,31,39)(34,38,40,36)(1,4,5,3)(2,6,7,8)(11,18)(14,22)(17,19)(21,23)(25,29,30,31)(26,33,28,39)(27,36,37,38)(32,34,35,40)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.