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