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