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