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