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