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