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