For example, take the 2004 draft. You could start this lineup of 2004 draftees, all players taken within the first 53 picks:
QB E Manning / Roethlisberger / P Rivers
RB Steven Jackson / K Jones / T Bell
WR L Fitzgerald / R Williams / L Evans
TE Winslow Jr / Watson
LT ??
LG Snee
C Smiley?? J Grove
RG V Carey
RT S Andrews
LDE K Udeze
LDT T Harris, M Tubbs
RDT V Wilfork, I Olshansky
RDE W Smith
OLB DJ Williams, K Dansby, Daryl Smith
MLB Vilma
CB D Hall / D Robinson, C Gamble
FS S Taylor (RIP)
SS B Sanders
Now obviously, you'd have to patch together an o-line (and Shawn Andrews and Chris Snee are very nice starts). But take a look at those skill position players! And that defense, especially the DTs and back 7! That team should win a Super Bowl.
And if you did a GREAT job drafting, you would go undefeated. For example, I didn't even mention DE Jared Allen, DT Corey Williams, S Gibril Wilson, T Max Starks, TE Cooley, LB Shaun Phillips, etc because they weren't selected in the first 53 picks in 2004.