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