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