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