The England defender tweeted that the FA were a "bunch of t***s" after he was criticised by the report explaining why John Terry was banned for racially abusing Anton Ferdinand.
Di Matteo said after Chelsea's 4-1 win against Norwich: "We have a social media policy and there will be disciplinary action against Ashley Cole."
Cole posted his message tweet after seeing TV coverage of the FA's written reasons for the Terry verdict, which were heavily critcal of Cole and Chelsea club secretary Dave Barnard.
A section entitled 'evolution of Ashley Cole's evidence' claimed Cole had amended his witness statement to support Terry's defence.
Cole tweeted: "Hahahahaa, well done #fa I lied did I, #BUNCHOFT***S".
Although he later apologised "unreservedly", his outburst has heaped more negative publicity on Chelsea, who were already reeling after Terry was banned for four matches following his clash with Ferdinand in a game against QPR last season.
The club cannot take any action against Terry until the end of any appeal process.
Di Matteo said on Friday: "At the moment he is our captain."
Both players completed 90 minutes against Norwich.