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