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