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