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