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