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