One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6,9,12)(7,11,8,10)(13,14,16,19)(15,21,23,18)(17,20,25,28)(22,27,24,26)(1,2)(3,4)(5,7,9,8)(6,10,12,11)(13,15)(14,18)(16,23)(17,22)(19,21)(20,26)(24,25)(27,28)(2,4) involution — undirected(2,4)(5,7,9,8)(6,11,12,10)(15,22)(17,25)(18,26)(20,28)(21,27)(23,24)(5,8,9,7)(6,11,12,10)(14,19)(18,21)(20,28)(26,27)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.