You really do need grout for your backsplash, for a proper job that is waterproof and easy to clean. Having said that, I once did a "just for now" refreshing of my tiny kitchen to hold it over for a while until I could afford to totally gut it and start over. I didn't want to bother grouting in some inexpensive tiles as a backsplash because I thought they would only be there for a short time. I painted the backsplash area a similar colour to the tiles, so the stark white plaster would not show through the cracks between the tiles and then lightly glued the tiles to the wall, butting them up directly to one another. Little did I know that I was about to get laid off from my job and it would be 8 years before I could afford to do the renovation I desired. The ungrouted tile backslash held up beautifully and because I was careful, remained dry and clean for that whole time. I just finally did the kitchen reno this past winter and they stayed stuck tight to the plaster as I tore it out. :-)

I think you should use white so the kitchen doesn't look choppy ,but if you still want color try this idea

Tiles are one way to introduce some pops of colour in your kitchen. If you are worried about the grout discolouring, use epoxy grout which is more resilient to liquid staining. Also, if you use a coloured grout, discolouration will be less noticeable. If you choose textured tiles with rectilinear edges, grout lines are almost invisible. Using tiles can look more traditional compared to glass or stainless steel. The problem with stainless steel is keeping it looking good. Drip marks and grease are instantly noticeable. Glass is less obvious when splashed. They are both more industrial and modern looking. What about using the same material that makes up your worktop as the splashback? Most manufacturers of manmade worktops also do an 11mm thick splashback and upstand.

Running the upstand behind the hob looks absolutely fine, seen it plenty of times and customers have always been happy, the only slight downside is large pans and woks can be up against the upstand as its thicker than your tiles but thats being really picky. Personnally i prefer this look then stopping the upstand, then stepping back for your splashback tiles and then stepping forward again and restarting the upstand and its easier to keep clean as well with no little corners for dirt to get trapped.