Use super glue. For bigger pieces, 'stitch' the pieces together by starting at one end and gluing around. Zip kicker also comes in handy to instantly set the glue. Use a hairdryer to soften the pieces before trimming. It can also make assembly easier when the vinyl is soft. I can't remember the layout of the halycon facehugger parts.
It should be a fleshy/tan/yellowish color.