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