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)(15,22)(16,21)(17,19)(25,28)(26,27) involution — undirected(1,2)(3,4)(6,9)(10,12)(13,14,18,20)(15,25,26,16)(17,23,19,24)(21,27,28,22)(5,7,8,11)(6,10,9,12)(13,15,18,26)(14,21,20,28)(16,23,25,24)(17,27,19,22)(2,4)(13,16)(14,22)(15,24)(17,28)(18,25)(19,21)(20,27)(23,26) involution — undirected(6,9)(10,12)(13,17,18,19)(14,23,20,24)(15,22,26,27)(16,28,25,21)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.