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