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