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