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