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