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