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