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