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