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