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