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