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