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