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