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