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