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