A plaid is an article of clothing worn over the left shoulder of a male and worn over the right shoulder of a female and comes from Gaelic ,plaide, "a blanket". Some plaids have a pattern of colours which is correctly referred to as a "tartan". Some plaids worn by the irish have solid colors, one of which is called the "Fringed Fly Plaid" which is saffron in colour, a shade of yellow.
Referring to a tartan, the design on some plaids, as "plaid" is like referring to a checked black and white pattern as a "table cloth" when all table clothes do not necessarily have a checked pattern and checked patterns can appear on skirts, sofas, floor tile and so on!
He's wearing a saffron plaid over his shoulder and is wearing a saffron kilt to match.