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