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