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