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