Big E Langston is the strongest guy there now - 711 squat (raw, no knee wraps), 529 bench (575 in the gym), 799 pound deadlift. Cesaro for his bodyweight also appears to be insanely strong.
Warlord was most definitely a monster among a much bigger locker room back in the day. A lot of the more recent guys (including Brock Lesnar) said that Kane in his prime was the strongest guy in the locker room - nobody could beat him at arm wrestling.
Cena is strong but there is no way he is (or was in the past) natural, although he strongly claims to have been.