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