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