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