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