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