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