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