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