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