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