[CREATURE_TILE:'M'][COLOR:0:0:1]
This right here controls the tile used and the color of said tile I believe. Right now it looks like it shows up as an uppercase M... Color black I think? I forgot how the colors work, if it's just rgb or not.
The Mayday graphics use the M tile as well, apparently, from looking at the raws from DFG. I think this is because the graphics setting ignores this line? Yeah probably, except for creatures in placed cages I think, so it's be editing the graphics text files you want.
Are you using the Mayday pack? If so then I think you'll need to go to your graphics folder and edit graphics_mayday.txt and add this to the bottom of the file or I believe anywhere under where it says [TILE_PAGE:MANS][FILE:mayday/mans.png][TILE_DIM:16:16][PAGE_DIM:12:17]:
[CREATURE_GRAPHICS:GRANITE_GOLEM]
[DEFAULT:MANS:0:14:AS_IS:DEFAULT]
That would use the tile for the Bronze Colossus.
[CREATURE_GRAPHICS:GRANITE_GOLEM]
[DEFAULT:MANS:1:14:AS_IS:DEFAULT]
And that would use the tile for the Iron Man.
You could also create your own tile and edit it in that mans.png, but you'd have to make sure it's in a valid spot and centered proper or it'll look messed up in game. You could put it right in the bottom left corner to make it easy and in that case that would mean you want to put in
[CREATURE_GRAPHICS:GRANITE_GOLEM]
[DEFAULT:MANS:0:17:AS_IS:DEFAULT]
As for the ranged attack, maybe a SOLID_GLOB attack with mat defined as granite boulders?
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:'X':SOLID_GLOB]
Where 'X' equals the name of the material projected as defined in the creature file.
I've never done this so I'm not sure how it works, I just grabbed that from the wiki. If I were you I'd look at some creatures who use attacks like this though, I believe some demons do but I don't know for sure.