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