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