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