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)(15,20)(16,22)(17,21)(18,23)(19,25)(24,28)(26,27) involution — undirected(5,7)(6,9)(8,11)(10,12)(13,15,18,24)(14,19,23,27)(16,25,17,26)(20,22,28,21)(1,2,3,4)(7,11)(9,12)(15,24)(19,27)(20,28)(25,26)(7,11)(9,12)(13,15)(14,20)(16,26)(17,25)(18,24)(19,21)(22,27)(23,28) involution — undirected(6,10)(9,12)(13,16,18,17)(14,21,23,22)(15,25,24,26)(19,20,27,28)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.