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)(15,19)(16,20)(17,18)(21,22,25,26)(23,27,28,24)(6,9)(7,11)(14,17)(15,20)(22,26)(24,27) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,15,18,20)(14,19,17,16)(21,23,25,28)(22,27,26,24)(1,2)(3,4)(5,6)(7,10)(8,9)(11,12)(13,16)(14,15)(17,20)(18,19) involution — undirected(5,7,8,11)(6,10,9,12)(13,17,18,14)(15,16,20,19)(21,24,25,27)(22,28,26,23)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.