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