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