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