Cover of English novel redesigned with purple on the outside (8)
I believe the answer is:
envelope
'cover' is the definition.
(I've seen this before)
'english novel redesigned with purple on the outside' is the wordplay.
'english' becomes 'e' (abbreviation).
'redesigned with' indicates an anagram.
'on the outside' means to remove the middle letters.
'purple' with its middle taken out is 'pe'.
'novel' with its letters anagrammed with 'pe' makes 'nvelope'.
'e'+'nvelope'='ENVELOPE'
'of' is the link.
(Other definitions for envelope that I've seen before include "Item of mail" , "Postal wrapper" , "Covering for letter" , "skin?" , "Even pole, strangely, can contain a letter" .)