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