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