Farmer,who celebrates his 72nd birthday today, was known for his skill at taking penalties and made 281 league appearances for the Bantams/Sky Blues from 1958-59 until October 1967 when he joined Notts County.
He retired from playing in 1970 and worked at Massey Ferguson.
Coventry City Chairman Ray Ranson is also expected to address the Diamond Club members and guests at the sold out lunch.