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