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