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