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