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