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