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