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