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