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)(15,19)(16,21)(17,22)(18,25)(20,24)(23,27)(26,28) involution — undirected(1,2,4,3)(5,7,9,8)(6,10,11,12)(13,14,16,21)(15,20,23,28)(17,25,18,22)(19,26,27,24)(5,8,9,7)(6,10,11,12)(13,15)(14,19)(16,23)(17,26)(18,24)(20,25)(21,27)(22,28)(1,3,4,2)(13,15)(14,20)(16,23)(17,24)(18,26)(19,25)(21,28)(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.