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