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