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