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