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)(14,20)(15,25)(17,19)(21,28)(22,27)(23,24)(2,4)(13,14,18,23)(15,22,25,28)(16,27,26,21)(17,24,19,20)(5,7,8,12)(6,9,10,11)(13,15,18,25)(14,21,23,27)(16,17,26,19)(20,22,24,28)(13,16)(14,22)(15,17)(18,26)(19,25)(20,27)(21,24)(23,28) involution — undirected(13,17,18,19)(14,20,23,24)(15,26,25,16)(21,22,27,28)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.