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