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