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