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