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