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