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