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