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