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